Meeting report: 4th Biennial Congress of the International Eosinophil Society

Abstract

There is currently a scientific debate regarding the role ofthe eosinophil in health and disease, in particular inallergic diseases (1–5). Therefore, the 4th biennial meetingof the International Eosinophil Society (May 25–29,2005, Bern, Switzerland) received great attention. Themeeting was organized by Dr H.-U. Simon (Switzerland),and was attended by 150 global participants. The meetinghonored Dr Christopher J. F. Spry, who delivered thefirst Paul Ehrlich Lectureship of the InternationalEosinophil Society for his more than 30 years ofoutstanding contributions to the field of eosinophilresearch.Several new views about the role of these enigmaticcells in immunity and disease emerged. Two differentgenetically engineered eosinophil-deficient mice providedthe basis for a profusion of animated discussions. Usingthese mice, several investigators (J. Lee, Arizona; C.Gerard, Boston; and P. Fulkerson, Cincinnati) demon-strated a critical role for eosinophils in experimentalasthma, yet there was considerable discussion about thespecific parameters of disease pathophysiology affectedby eosinophils, particularly the role of eosinophils inairway hyperreactivity. The role of eosinophils in para-sitic worm infections was reviewed (F. Finkelman,Cincinnati), and a role in controlling hepatotoxicityinduced during experimental Schistosoma mansoni infec-tion (K. Dyer and H. Rosenberg, NIH) was suggestedbased on experiments using eosinophil-deficient mice.Indeed, particular single nucleotide polymorphisms(SNPs) in the eosinophil cationic protein were shown tobe strongly associated with host responses to parasiteinfection (P. Venge, Sweden).Several lines of evidence were presented that eosinoph-ils have an immunoregulatory role involving the produc-tion of substantial levels of cytokines, antigenpresentation (P. Weller, Boston), and targeting of Th1cells for apoptosis via indoleamine 2,3-dioxygenase (IDO)catabolism of tryptophan (R. Moqbel, Canada). A rolefor eosinophils in tissue remodeling and fibrogenesis inexperimental lung fibrosis in mice (S. Phen, Michigan andP. Foster, Australia), human atopy and asthma(A. B. Kay, UK), and human eosinophilic esophagitis(G. Furuta, Boston and A. Straumann, Switzerland) waspresented, including a role for eosinophils in angiogenesisin these processes (F. Levi-Schaffer, Israel). In addition,interactions between eosinophils and nerves were dis-cussed as possible mechanisms for airway hyperreactivityin asthma (R. Costello and M. T. Walsh, Ireland). Theparticipation of eosinophils in innate immunity by directinteraction with various microorganisms including fungi(H. Kita, Rochester, MN, USA) and mycobacteria(M. Capron, France), possibly via Toll-like receptor-2,was presented.Advances in understanding the transcriptional appar-atus responsible for eosinophil lineage-specific geneexpression and development (involving unique doubleGATA-1 transcription factor-binding sites, and thefactors PU.1 and C/EBP